Install crashes under XP

I tried installing 1.0.303.52 on XP SP3, 32 bit. It immediately crashed with a dialog box titled "Vivaldi Installer". The message said "Vivaldi installer has encountered a problem and needs to close. we are sorry for the inconvenience. Please tell Microsoft about the problem. ..." The click on the box for information contains nothing I could understand. The has a box to send a report to M$. I clicked on it but got nothing back. I tried it four times and got the same result each time.

Vivaldi is built on the Chromium (Blink) rendering engine, and recent versions of that require P4 or newer processors with SSE2 instruction support. AMD Athlon XP or Athlon 2000 series or 3000 series, for instance, will not cut it. If your processor is not compatible, you will normally get an error message like: "Windows cannot install this program" or something like that. If you are running any RECENT version of Chrome (since about Aug 2014 - Jan 2015), then you should have SSE2 instruction support. Otherwise, it would throw the same error message when you tried to install it. It's true, SSE2 is good for media, and it's what makes it possible for Chrome and related browsers to show you videos, etc. using HTML5 rather than Flash, etc.

I'm pretty sure I've seen guys running older Chrome versions without even knowing it, because Chrome just quit updating when it detected an unsupported processor.

If your processor is up to snuff and you are getting a crash on install (I have never seen this, even on my XP machines), there is something else going on. The possibilities for why this failed run into the hundreds, if not the thousands - everything from bad installer (wrong MD5 sum, or 64-bit installer on a 32-bit system, etc.) to hardware incompatibility, to corrupted registry, to corrupted OS, to 3rd party security software, and on and on.

Maybe post your exact machine specs here (CPUID is a good way to detail them) along with any error code or the exact text of the error message, and hopefully someone can help you so suss it out.